able, is separable by the imagination;
and as every idea, that is separable by the imagination, may be
conceived to be separately existent; it is evident, that the existence
of one particle of matter, no more implies the existence of another,
than a square figure in one body implies a square figure in every one.
This being granted, I now demand what results from the concurrence of
these two possible ideas of rest and annihilation, and what must we
conceive to follow upon the annihilation of all the air and subtile
matter in the chamber, supposing the walls to remain the same, without
any motion or alteration? There are some metaphysicians, who answer,
that since matter and extension are the same, the annihilation of one
necessarily implies that of the other; and there being now no distance
betwixt the walls of the chamber, they touch each other; in the same
manner as my hand touches the paper, which is immediately before me.
But though this answer be very common, I defy these metaphysicians to
conceive the matter according to their hypothesis, or imagine the floor
and roof, with all the opposite sides of the chamber, to touch each
other, while they continue in rest, and preserve the same position. For
how can the two walls, that run from south to north, touch each other,
while they touch the opposite ends of two walls, that run from east
to west? And how can the floor and roof ever meet, while they are
separated by the four walls, that lie in a contrary position? If you
change their position, you suppose a motion. If you conceive any thing
betwixt them, you suppose a new creation. But keeping strictly to the
two ideas of rest and annihilation, it is evident, that the idea, which
results from them, is not that of a contact of parts, but something
else; which is concluded to be the idea of a vacuum.

The third objection carries the matter still farther, and not only
asserts, that the idea of a vacuum is real and possible, but also
necessary and unavoidable. This assertion is founded on the motion we
observe in bodies, which, it is maintained, would be impossible and
inconceivable without a vacuum, into which one body must move in order
to make way for another.. I shall not enlarge upon this objection,
because it principally belongs to natural philosophy, which lies without
our present sphere.

In order to answer these objections, we must take the matter pretty
deep, and consider the nature and origin of several ideas, le